whitespace

The sed (Stream Editor) is very powerful tool. Each line of input is copied into a pattern space. You can run editing commands on each input line to delete or change the input. For example, delete lines containing word DVD, enter:cat input.txt | sed ‘/DVD/d’

To Print the lines between each pair of words pen and pencil, inclusive, enter:$ cat input.txt sed -e '/^PEN/,/^PENCIL/p'